Today i updated from 18.1.0 to 18.5.0. After that, Office 2010 is doing some configuration and wants a new serial key. With the old key activation fails. Same on MSProject 2016. Downgraded to 18.1.0 again and installed the backup archives. Everything is working.
Please take a look on this issue. Reconfiguring of activated MS products deletes existing activations. I would like to upgrade without buying new licenses or serial keys.
Regards